Screw and light combination for instrument lighting

ABSTRACT

A mounting screw for an instrument includes a shank portion having a cutout on one side. A light bulb is cradled in the cutout to emit light laterally from one side relative to the axis of the screw. Conductive slip rings circumferentially extend over the opposite side of the shank portion in axially insulated spaced relationship such that when the mounting screw is inserted in a receiving screw hole in the instrument casing adjacent to the instrument dial, the dial is internally lighted, the screw serving the dual function of mounting the instrument and providing support for the internal lighting.

States Patent MacArthur,jr.

Primary Examiner- Louis .I. Capozi Attorney-Pastoriza and KellyABSTRACT: A mounting screw for an instrument includes a shank portionhaving a cutout on one side. A light bulb is cradled in the cutout toemit light laterally from one side relative to the axis of the screw.Conductive slip rings circumferentially extend over the opposite side ofthe shank portion in axially insulated spaced relationship such thatwhen the mounting screw is inserted in a receiving screw hole in theinstrument casing adjacent to the instrument dial, the dial isinternally lighted, the screw serving the dual function of mounting theinstrument and providing support for the internal 7 lighting.

PATENIEUUECZI an 3.629.568

INVENTOR.

ARNOLD LOYD HAN ES BY IG.5 FIG 4 F M2374? A770 NEVS SCREW AND LIGHTCOMBINATION FOR INSTRUMENT LIGHTING This invention relates generally toinstrument lighting and more particularly to a novel screw which mightbe used for mounting the instrument to a panel or securing portions ofthe instrument itself together and simultaneously serve to support alight source for illuminating the dial of the instrument.

BACKGROUND OF THE INVENTION It is becoming increasingly desirable toilluminate instrument dials internally. Particularly is such the case inaircraft instruments wherein external lighting sources in the cockpitcan be annoying to the pilot of the aircraft particularly because ofreflections from various other components in the cockpit.

It has been the practice, accordingly, to utilize miniature light bulbsinternally within the instrument in conjunction with a light wedge orlight-conducting material which affords a relatively uniformillumination of the instrument dial by a bulb located to one side withinthe instrument. The principal difficulty with such designs arises fromthe necessity of changing light bulbs when a bulb burns out. In mostinstances, changing of the bulb requires the removal of the entireinstrument from the panel. The instrument must then be taken apart forthe bulb change.

One particular design is such that the bulb can be changed from thefront but in this instance all of the mounting screws must be removedand the bulb change then effected.

BRIEF DESCRIPTION OF THE PRESENT INVENTION The present inventionprovides a novel internal lighting means for instruments which overcomesthe difficulties encountered heretofore in changing the internallighting bulbs.

More particularly, in accord with the invention the internal lightingbulb is incorporated in one or more of the mounting screws for theinstrument. By this arrangement, to change a bulb it is only necessaryto take out one or more of the mounting screws and install a new oneincorporating a fresh bulb.

The screw itself includes a shank portion merging into a reduceddiameter threaded portion. The shank portion includes a cutout on oneside cradling a light bulb so that light is emitted laterally from thisside relative to the axis of the screw. Suitable conductive slip ringscircumferentially extend over the opposite side of the shank portion inaxially spaced relationship to each other. When the screw is inserted inthe front of the instrument flange, an automatic connection is effectedfrom a power source to the light bulb through the slip rings.

The invention also contemplates a novel light wedge for distributing thelight from the bulb within the screw uniformly over the instrument sothat improved internal illumination results.

BRIEF DESCRIPTION OF THE DRAWINGS A better understanding of theinvention will be had by now referring to a preferred embodiment thereofas illustrated in the accompanying drawings in which:

FIG. 1 is an exploded perspective view of an aircraft instrument andpanel portion wherein the novel mounting screw is utilized for providinginternal illumination for the instrument;

FIG. 2 is a rear elevational view of the front mounting flange portionof the instrument of FIG. 1 taken in the direction of the arrows 22;

FIG. 3 is a fragmentary cross section taken in the direction of thesection line 3--3 of FIG. 2;

FIG. 4 is a side elevational view of the mounting screw of theinvention;

FIG. 5 is a perspective view of a light wedge in accord with a furtherfeature of the invention; and,

FIG. 6 illustrates a modified conventional type of light wedge which maybe utilized with the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIG.1 there is illustrated an instrument casing structure including a rearcylindrical portion 10, mounting flange portion 11, and cover I2. Thecover 12 mounts a front glass window I3 through which a dial I4 isvisible. A panel P includes a registering circular opening 15 such thatwhen the instrument is mounted to the rear of the panel, the dial willbe visible through this opening.

Normally, the mounting flange l1 and cover 12 will include registeredscrew openings such as indicated at l6, 17, I8, and 19 in turnregistering with panel openings 20, 21, 22, and 23. The instrument canthus be secured to the rear of the panel by inserting mounting screwsthrough these registered openings.

Thus far, the structure described corresponds to conventional typeinstruments and mountings. when it becomes necessary to change one ofthe internal dial illuminating bulbs, the four mounting screws must beremoved and the entire instrument separated from the back of the panel.The front cover can then be removed and the bulb replaced. Thisoperation is very expensive and time consuming. Further, it would beunsafe and difficult to effect such a bulb change during flight.

In accord with the present invention, at least one and preferably two ofthe mounting screws for the instrument is uniquely designed toincorporate the dial illuminating bulb. Thus, as shown in FIG. I thereis illustrated at 24 such a mounting screw receivable through theregistered openings 20 and 16. A resilient type locknut 25 cooperateswith the screw 24 to hold the instrument to the panel. As will bedescribed in greater detail subsequently, the screw 24 incorporates inone side a miniature light bulb such that when the screw is insertedthrough the panel into the instrument opening, proper illumination ofthe dial takes place. Accordingly, it is only necessary to remove thescrew and replace it with another screw incorporating a fresh light bulbshould the lighting fail. This operation can be easily carried our whilein flight if necessary without the necessity of disassembling theinstrument or separating it from the panel.

Referring now to FIG. 2, details of the improved internal lightingsystem will become evident. In FIG. 2, there is shown a rear view of thecover I2 of FIG. I as it would appear if it were removed from theinstrument and viewed from the rear. As shown, the upper corners includeslightly recessed areas 26. In the preferred embodiment of theinvention, a novel comer light wedge 27 of translucent light conductingmaterial is positioned in this recess and cooperates with the light bulbin the screw when the same has been received through the cover member. Abrush assembly 28 from which extend two resilient brushes 29 and 30serves to provide electrical current to the bulb within the screw whenthe screw is mounted through the opening. A similar brush assemblyarrangement is provided for the cover opening 17 on the other uppercorner of the cover member. The output leads for connection to a sourceof electrical energy to energize the bulbs are illustrated at 31 and 32.

In the side view of FIG. 3, the axially spaced relationship of thebrushes 29 and 30 adjacent to the inner edge of the bore opening I6 isclearly illustrated. In this view, the arrangement of the nuts 25 forreceiving the threaded portion of the screw is also clearly shown. Itwill be noted that the nut is permanently secured to the rear of theflange portion I1 and includes a small threaded area in a rear diaphragmlike portion. The arrangement is such that the rear diaphragm likeportion. The arrangement is such that the rear surface of the nut 25;that is the peripheral portion about the threaded opening of the nut mayresiliently flex inwardly as the screw is tightened. This arrangementpermits the rotational position of the screw to be oriented in a desireddirection without affecting the integrity of its holding power.

Referring now to FIG. 4 further details of the screw 24 will becomeevident. As shown, the screw includes a shank portion 33 merging into areduced diameter threaded portion 34. The shank portion includes acutout 35 on one side for cradling a light bulb 36. The filament for thelight bulb connects to conduetive sliprings circumferentially extendingover and substantially flush with the opposite side of the shank portionas indicated at 37 and 38. These sliprings are insulated from each otherand from the shank portion of the screw. When the screw is assembled inthe opening 16 of the cover of FIG. 2 and oriented so that the cutout isfacing radially inwardly towards the dial, the slip ring brushes 29 and30 will properly engage the slip rings 37 and 38 so that energy can besupplied to the bulb.

Referring now to FIG. there is illustrated in greater detail one of thecomer light wedges such as the wedge 27. As shown, the wedge compriseslight conducting material having a thickness corresponding substantiallyto the axial length of the cutout in the shank portion of the screw andan arcuate rear edge surface 39 substantially designed to cover thecutout portion of the screw when the elements are assembled. The frontedge surface of the light wedge 27 is indicated at 40 and is preferablyarcuate with a radius of curvature greater than the rear arcuate edge39. However, this front edge surface 40 could be flat.

The, side edges of the corner light wedge between the ends of the rearand front arcuate edges are straight and at right angles to each otherso as to nest within the particuiar flange structure illustrated. Theseside surfaces include an internal reflective coating so that lightconducted by the corner wedge is reflected from the rear surfaces to allpass out the front arcuate surface and provide substantially uniformillumination over a given quadrant of the dial for the instrument.

FIG. 6 illustrates an alternative type of light wedge 43 correspondingto conventional types of light wedges except for extended portions 44and 45 surrounding the cutouts for distributing light from the sourcesover the dial surface.

OPERATION Most aircraft instruments and other types of instruments havestandard mountings or screw openings some place adjacent to the dial ofthe instrument. Thus, there is really no necessity for having to effectany major modification of the instrument itself or the panel. It isessential, however, to provide the corner recess such as described at 26in the comers of the covers or flanges where the screw openings occur toprovide communication between one side of the opening and the interiorspace between the front window glass and dial. The brush assembly forcooperation with the sliprings is inserted in part of the recess toposition the brushes 29 and 30 as described. Otherwise, no othermodifications are necessary so it will be evident that presentinstruments may be adapted to the invention. Either the corner lightwedge structure described in FIG. 5 or the modified type of conventionallight wedge 43 of FIG. 6 may be utilized without necessitating furthermodifications.

The instrument is mounted in the usual fashion with conventionalmounting screws except for at least one of the screws which incorporatesthe light bulb. In the particular embodiment illustrated in FIG. I, itis preferable to provide two light bulbs at the upper left and righthand corners. Thus, screws such as the screw 24 are substituted for theconventional type screws and tightened within the screw openings.Because of the resiliency of the rear portion of the nut 25, the screwmay be rotated as necessary to direct the small arrow on the head of thescrew as illustrated in FIG. I in a direction pointing radially inward.This orientation assures that the cutout on the shank portion of thescrew is directed inwardly so that the light will be properly directed.Further, this orientation assures proper positioning of the slipringsfor engaging by the brushes 29 and 30 as described in FIGS. 2 and 3.

After the instrument has been assembled which assembly can easily bedone from the front of the panel, there is never any necessity fordisassembling the instrument or removing it from the panel in order tochange a light bulb. All that is necessary is to remove the screwcontaining the light bulb and simply bodily substitute in another screwincorporating a light bulb in accord with the invention. This operationcan be done during flight of the aircraft if necessary.

From the foregoing description, the advantages of the present inventionwill be immediately evident. First and foremost, access is enormouslysimplified since, as described, a bulb may be changed directly from thefront of the panel without any necessity of disassembling the instrumentitself or removing it from the panel. Such convenience results in aconsiderable savings in labor costs and maintenance expenses. Further, abulb change can be effected far more rapidly than has been possibleheretofore.

Second, no major modification is required of conventional instrumentsexcept for the small provision of recesses to provide communicationbetween the screw holes and the space between the dial and glass and theincorporation of the brushes for providing current to the bulb when thescrew is inserted. None of the exterior dimensions of the instrument isaffected by such modifications. Further, conventional type light wedgesmay still be used, such wedges preferably being modified slightly toprovide good light conductivity from the bulbs as by means of theextended side portions 44 and 45 as described in FIG. 6. The use ofeither the light wedge of FIG. 6 or the corner light wedge described inFIG. 5 assures excellent uniform dispersal of light over the entire faceof the dial when a screw is used in each upper corner. I

It should be understood that while an aircraft instrument has beendescribed, the invention is applicable to any type of instruments havinga dial which requires internal illumination and wherein there isnormally provided a screw hole for a mounting screw or an assembly screwadjacent to a side of the dial.

From the foregoing description, it will be evident that the presentinvention has provided a greatly improved internal lighting system forinstruments wherein the difficulties in bulb changing characterizingprior art devices have been wholly eliminated.

What is claimed is:

l. A mounting screw for an instrument, said screw having a shank portionmerging into a reduced diameter threaded portion, said shank portionincluding a cutout on one side; a light bulb cradled in said cutout toemit light laterally from said one side relative to the axis of saidscrew; and conductive sliprings circumferentially extending over andsubstantially flush with the opposite side of said shank portion inaxially spaced insulated relationship to each other and the shankportion of said screw, and connected to said bulb for passing current tosaid bulb.

2. The subject matter of claim 1, including a corner light wedge oflight-conducting material having a thickness corresponding substantiallyto the axial length of said cutout in said shank portion of said screwand an arcuate rear edge surface substantially covering said cutout anda front edge surface, the side edges between the ends of the rear andfront edges being straight and at right angles to each other andincluding an internal reflective coating whereby said light is uniformlydispersed over a given quadrant by said corner light wedge.

3. in combination with an instrument having a forwardly facing dial andsurrounding casing structure with at least one screw hole to one side ofsaid dial with its axis substantially normal to the plane of said dial,a screw receivable in said hole from the front of said instrument, saidscrew having a shank portion incorporating a light source for emittinglight laterally relative to the axis of said screw whereby when saidscrew is received in said screw hole said dial is internallyilluminated.

4. The subject matter of claim 3, including light wedge means withinsaid casing structure for coupling light from said source anddistributing it over an area for substantially uniformly illuminatingsaid dial.

5. The subject matter of claim 4, in which said light wedge meanscomprises a corner light wedge of light-conducting material, said shankportion of said screw having a cutout in one side from which said lightemanates, said light wedge having a thickness correspondingsubstantially to the axial length of said cutout and having an arcuaterear edge surface substantially covering said cutout and a front edgesurface, the side edges between the ends of the rear and front edgesbeing straight and at right angles to each other and including aninternal reflective coating whereby said light is uniformly dispersedover a given quadrant by said corner wedge.

6. In combination with an instrument having a front forwardly facingdial and surrounding mounting flange with mounting screw holes forsecuring the instrument to the rear of a panel in registration with apanel opening through which said dial may be seen from the front of saidpanel, at least one mounting screw receivable in one of the screw holesin the mounting flange by passing the same through a registered hole inthe panel from the front of the panel to one side of said dial, saidscrew having a shank portion incorporating a light source for emittinglight laterally relative to the axis of said screw whereby when thescrew is received in the screw hole it serves a dual function ofsecuring the instrument to the panel and internally illuminating thedial.

7. The subject matter of claim 6, in which said shank portion of saidscrew has a cutout in one side from which said light emanates, saidlight source comprising a light bulb cradled in said cutout to emitlight laterally from the one side relative to the axis of the screw; andconductive slip rings circumferentially extending over and substantiallyflush with the opposite side of said shank portion in axially spacedinsulated relationship to each other and the shank portion of saidscrew, and connected to said bulb for passing current through said bulb.

8. The subject matter of claim 7, including a corner light wedge oflight-conducting material having a thickness corresponding substantiallyto the axial length of said cutout in said shank portion of said screwand an arcuate rear edge surface substantially covering said cutout andan arcuate front edge surface of substantially greater radius ofcurvature than said rear surface, the side edges between the ends of therear and front arcuate edges being straight and at right angles to eachother and including an internal reflective coating whereby said light isuniformly dispersed over a given quadrant of said dial by said cornerlight wedge.

1. A mounting screw for an instrument, said screw having a shank portionmerging into a reduced diameter threaded portion, said shank portionincluding a cutout on one side; a light bulb cradled in said cutout toemit light laterally from said one side relative to the axis of saidscrew; and conductive sliprings circumferentially extending over andsubstantially flush with the opposite side of said shank portion inaxially spaced insulated relationship to each other and tHe shankportion of said screw, and connected to said bulb for passing current tosaid bulb.
 2. The subject matter of claim 1, including a corner lightwedge of light-conducting material having a thickness correspondingsubstantially to the axial length of said cutout in said shank portionof said screw and an arcuate rear edge surface substantially coveringsaid cutout and a front edge surface, the side edges between the ends ofthe rear and front edges being straight and at right angles to eachother and including an internal reflective coating whereby said light isuniformly dispersed over a given quadrant by said corner light wedge. 3.In combination with an instrument having a forwardly facing dial andsurrounding casing structure with at least one screw hole to one side ofsaid dial with its axis substantially normal to the plane of said dial,a screw receivable in said hole from the front of said instrument, saidscrew having a shank portion incorporating a light source for emittinglight laterally relative to the axis of said screw whereby when saidscrew is received in said screw hole said dial is internallyilluminated.
 4. The subject matter of claim 3, including light wedgemeans within said casing structure for coupling light from said sourceand distributing it over an area for substantially uniformlyilluminating said dial.
 5. The subject matter of claim 4, in which saidlight wedge means comprises a corner light wedge of light-conductingmaterial, said shank portion of said screw having a cutout in one sidefrom which said light emanates, said light wedge having a thicknesscorresponding substantially to the axial length of said cutout andhaving an arcuate rear edge surface substantially covering said cutoutand a front edge surface, the side edges between the ends of the rearand front edges being straight and at right angles to each other andincluding an internal reflective coating whereby said light is uniformlydispersed over a given quadrant by said corner wedge.
 6. In combinationwith an instrument having a front forwardly facing dial and surroundingmounting flange with mounting screw holes for securing the instrument tothe rear of a panel in registration with a panel opening through whichsaid dial may be seen from the front of said panel, at least onemounting screw receivable in one of the screw holes in the mountingflange by passing the same through a registered hole in the panel fromthe front of the panel to one side of said dial, said screw having ashank portion incorporating a light source for emitting light laterallyrelative to the axis of said screw whereby when the screw is received inthe screw hole it serves a dual function of securing the instrument tothe panel and internally illuminating the dial.
 7. The subject matter ofclaim 6, in which said shank portion of said screw has a cutout in oneside from which said light emanates, said light source comprising alight bulb cradled in said cutout to emit light laterally from the oneside relative to the axis of the screw; and conductive slip ringscircumferentially extending over and substantially flush with theopposite side of said shank portion in axially spaced insulatedrelationship to each other and the shank portion of said screw, andconnected to said bulb for passing current through said bulb.
 8. Thesubject matter of claim 7, including a corner light wedge oflight-conducting material having a thickness corresponding substantiallyto the axial length of said cutout in said shank portion of said screwand an arcuate rear edge surface substantially covering said cutout andan arcuate front edge surface of substantially greater radius ofcurvature than said rear surface, the side edges between the ends of therear and front arcuate edges being straight and at right angles to eachother and including an internal reflective coating whereby said light isuniformly dispersed over a given quadrant of said dial by said cornerlight wedge.